UIButton 上的 iOS NSAttributedString

iOS NSAttributedString on UIButton(UIButton 上的 iOS NSAttributedString)

问题描述

我使用的是 iOS 6，所以属性字符串应该很容易使用，对吧?嗯……没那么多.

I'm using iOS 6, so attributed strings should be easy to use, right? Well... not so much.

我想做什么:

使用 UIButton 的自定义子类(它不会对 titleLabel 进行任何自定义)，我想要一个多行的属性标题，即:

Using a custom subclass of UIButton (it doesn't do anything custom to titleLabel), I'd like to have a multi-line, attributed title that is:

1. 第一行全部大写(我意识到这不是属性的一部分)
2. 粗体在第一行
3. 下划线在第一行
4. 第二行的正常"权重
5. 第二行无下划线
6. 以两条线为中心

到目前为止，我已经能够得到 # 的 1 到 5(至少，我认为我做到了，但当前的测试产生了多行文本的错误)，但是当我尝试做某事时(任何事情！) 使文本居中，我的应用程序不断崩溃.当我尝试让所有 6 项工作(通过各种方法)时，我收到以下崩溃/错误:

I've been able to get #'s 1 through 5 so far (at least, I thought I did, but current testing is yielding errors with multi-line text), but when I tried to do something (anything!) to get the text to be centered, my app keeps crashing. When I try to get all 6 items working (through various methods), I get the following crash/error:

Terminating app due to uncaught exception 
'NSInternalInconsistencyException', reason: 
'NSAttributedString invalid for autoresizing, 
it must have a single spanning paragraph style
(or none) with a non-wrapping lineBreakMode.'

根据我的尝试，我似乎可以选择以下选项之一，但不能同时拥有:

Based on what I've tried, it appears that I can have one of the following options, but not both:

1. 多行居中标签
2. 属性标签

如果我必须，我可以接受其中一个或另一个，但我不敢相信我不能拥有一个看似相当简单的概念.

I can live with one or the other if I must, but I can't believe that I can't have what seems to be a fairly straightforward concept.

谁能告诉我我做错了什么?

Can someone please tell me what I've got wrong?

这是我正在尝试的代码的最后一次迭代:

Here's the last iteration of the code I'm trying:

NSMutableParagraphStyle *style = [[NSParagraphStyle defaultParagraphStyle] mutableCopy];
[style setAlignment:NSTextAlignmentCenter];
[style setLineBreakMode:NSLineBreakByWordWrapping];

UIFont *font1 = [UIFont fontWithName:@"HelveticaNeue-Medium" size:20.0f];
UIFont *font2 = [UIFont fontWithName:@"HelveticaNeue-Light"  size:20.0f];
NSDictionary *dict1 = @{NSUnderlineStyleAttributeName:@(NSUnderlineStyleSingle),  
                        NSFontAttributeName:font1};
NSDictionary *dict2 = @{NSUnderlineStyleAttributeName:@(NSUnderlineStyleNone),    
                        NSFontAttributeName:font2};

NSMutableAttributedString *attString = [[NSMutableAttributedString alloc] init];
[attString appendAttributedString:[[NSAttributedString alloc] initWithString:@"LINE 1
"    attributes:dict1]];
[attString appendAttributedString:[[NSAttributedString alloc] initWithString:@"line 2"      attributes:dict2]];
[[self buttonToStyle] setAttributedTitle:attString forState:UIControlStateNormal];
[[[self buttonToStyle] titleLabel] setNumberOfLines:0];
[[[self buttonToStyle] titleLabel] setLineBreakMode:NSLineBreakByWordWrapping];

推荐答案

在我看来，您好像忘记在代码中使用您设置的样式"对象......您只是实例化了它.您应该将代码修改为如下所示:

It looks to me like you forgot in your code to use the "style" object that you set up.. you just instantiated it. You should modify your code to look like this:

NSMutableParagraphStyle *style = [[NSParagraphStyle defaultParagraphStyle] mutableCopy];
[style setAlignment:NSTextAlignmentCenter];
[style setLineBreakMode:NSLineBreakByWordWrapping];

UIFont *font1 = [UIFont fontWithName:@"HelveticaNeue-Medium" size:20.0f];
UIFont *font2 = [UIFont fontWithName:@"HelveticaNeue-Light"  size:20.0f];
NSDictionary *dict1 = @{NSUnderlineStyleAttributeName:@(NSUnderlineStyleSingle),
                        NSFontAttributeName:font1,
                        NSParagraphStyleAttributeName:style}; // Added line
NSDictionary *dict2 = @{NSUnderlineStyleAttributeName:@(NSUnderlineStyleNone),
                        NSFontAttributeName:font2,
                        NSParagraphStyleAttributeName:style}; // Added line

NSMutableAttributedString *attString = [[NSMutableAttributedString alloc] init];
[attString appendAttributedString:[[NSAttributedString alloc] initWithString:@"LINE 1
"    attributes:dict1]];
[attString appendAttributedString:[[NSAttributedString alloc] initWithString:@"line 2"      attributes:dict2]];
[self.resolveButton setAttributedTitle:attString forState:UIControlStateNormal];
[[self.resolveButton titleLabel] setNumberOfLines:0];
[[self.resolveButton titleLabel] setLineBreakMode:NSLineBreakByWordWrapping];

请注意，我只添加了定义 NSParagraphStyleAttributeName 的行.其他一切都是一样的.这就是我得到的按钮:

Note that I only added the lines that define the NSParagraphStyleAttributeName.. everything else is the same.. and this is what I get for the button:

这里是 Swift 3.0

And here it is in Swift 3.0

let style = NSMutableParagraphStyle()
style.alignment = .center
style.lineBreakMode = .byWordWrapping

guard
    let font1 = UIFont(name: "HelveticaNeue-Medium", size: 20),
    let font2 = UIFont(name: "HelveticaNeue-Light", size: 20)  else { return }

let dict1:[String:Any] = [
    NSUnderlineStyleAttributeName:NSUnderlineStyle.styleSingle.rawValue,
    NSFontAttributeName:font1,
    NSParagraphStyleAttributeName:style
]

let dict2:[String:Any] = [
    NSUnderlineStyleAttributeName:NSUnderlineStyle.styleNone.rawValue,
    NSFontAttributeName:font2,
    NSParagraphStyleAttributeName:style
]

let attString = NSMutableAttributedString()
attString.append(NSAttributedString(string: "LINE 1", attributes: dict1))
attString.append(NSAttributedString(string: "line 2", attributes: dict2))

button.setAttributedTitle(attString, for: .normal)
button.titleLabel?.numberOfLines = 0
button.titleLabel?.lineBreakMode = .byWordWrapping

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